In a rod body for a fishing rod of this type, a prepreg molded into a tape or a prepreg molded into a sheet is sometimes used. A prepreg tape has an elongated shape with small-width and comprises reinforcing fibers oriented in the longitudinal direction of the prepreg tape.
A prepreg sheet has a length corresponding to the length of a rod body for a fishing rod and a width necessary for forming a tubular body so as to take an approximately trapezoidal shape.
An inner layer or an outer layer is formed using such a prepreg tape by helically winding the prepreg tape around a mandrel in the rod axis direction in an overlapping state.
While the prepreg tape is used for both the inner layer and the outer layer, directions in which the prepreg tape is helically wound are the same in both layers. Specifically, as shown in FIGS. 3 and 5 of the Patent Document 1, the winding direction of the prepreg tape is set to the same right-handed direction for both inner and outer layers.
Consequently, since the reinforcing fibers of the prepreg become oriented in the direction identical with the direction of the prepreg tape, the reinforcing fibers of the prepreg and the prepreg tape end up being arranged in the same direction. While the reinforcing fibers provide a tensile matching force to ensure sufficient torsional rigidity when subjected to a torsional force in the right-handed direction, the reinforcing fibers are unable to provide a matching tensile force when subjected to a torsional force in a left-handed direction and causes a reduction in torsional rigidity.    Patent Document 1: Japanese Patent Application Laid-open No. 2008-263819
Besides configurations such as that described above, there is also a configuration in which prepreg tapes are arranged on the inside and the outside so as to sandwich a prepreg sheet as the intermediate layer.    Patent Document 2: Japanese Utility Model Publication No. S63-32631
In the invention described in Patent Document 2, an intermediate layer is formed by winding a prepreg sheet having a length corresponding to the total length of a rod body for a fishing rod, and the inner layer positioned on the inside of the intermediate layer is formed by helically winding a prepreg tape with small-width in a rod axis direction at a wider pitch than the width of the prepreg tape. On the other hand, the outer layer positioned on the outside of the intermediate layer is formed by helically winding a prepreg tape with small-width in a rod axis direction at a wider pitch than the width of the prepreg tape. In addition, the winding direction of the prepreg tape forming the outer layer is set opposite to a winding direction of the prepreg tape forming the inner layer.
However, even with a configuration in which winding directions of prepreg tapes positioned on the inside and the outside are set opposite to each other as described above, since the prepreg tapes are simply wound at a wide pitch, the inner layer and the outer layer merely reinforce the intermediate layer and do not provide sufficient torsional rigidity.